Fossil Fishes of the Upper Karroo Beds of South Africa. 259 



In the collection obtained by Dr. Kannemeyer there is a tail with 

 the dorsal and anal fins, which almost certainly belong to this 

 species. 



OXYGNATHUS BROWNI, Sp. 11OV. 



Of this large Palaeoniscid fish there is only one good specimen in 

 the collection which will be taken as the type. There is, however, a 

 second smaller specimen of which much of the head is preserved 

 and the anterior half of the body. It is difficult to compare the two 

 specimens, and it is thus not quite certain that the two belong to the 

 same species. As, however, the two are at least closely allied, and 

 probably represent the same animal, the second specimen will be 

 used for the description of the cranial characters. 



General Form. The type specimen when complete probably 

 measured 310 mm. in length, and the greatest depth of the trunk 

 is 75 mm. The dorsal, anal, and caudal fins at least are large and 

 powerful, \vhile the scales are relatively small and thin. 



Head and Opercular Apparatus. In the type specimen only the 

 upper and back part of the head is preserved. The opercular is large 

 and rhomboidal, and about a half longer than broad. In front of it 

 lies a narrow preopercular, about half the width of the opercular. 

 Above these two bones is a large squarnosal imperfectly preserved. 

 Between the upper part of the opercular and the preopercular is 

 apparently a small triangular bone agreeing in position with the bone 

 figured as " hyornandibular " by Traquair in his figure of the head 

 of Oxygnatlius ornatus, but I do not think it can be regarded as 

 hyornandibular in the present specimen as it is finely tuberculated 

 like the opercular bones, and thus presumably a membrane bone. 

 Most probably it corresponds to the element marked x, and called a 

 " supplementary plate " by Traquair in his restoration of the head of 

 Eloniclitliys pectinatus. Only a small part of the subopercular is 

 preserved. 



In the second specimen the ocular and preocular regions are 

 missing, but the posterior half is fairly well preserved. The surface 

 of the bones is weathered off, but well-marked impressions of many 

 of the bones remain. The opercular at its widest part measures 

 8 mm., and its greatest length over the long diagonal is about 



18 mm. The subopercular is about a half broader than deep. 

 Immediately below it are the series of branchials. There are 



19 preserved, and it is unlikely that more than one or two are 

 missing. Immediately in front of the opercular and subopercular is 

 a long narrow hyornandibular exposed by the removal of the " sup- 



